Transferrin is an essential ingredient used in cell culture media due to its crucial role in regulating cellular iron uptake, transport, and utilization. It is also a promising drug carrier used to increase a drug’s therapeutic index via the unique transferrin receptor-mediated endocytosis pathway. Due to the high risk of contamination with blood-borne pathogens from the use of human- or animal plasma-derived transferrin, recombinant transferrin is preferred for use as a replacement for native transferrin. We expressed recombinant human transferrin in rice (Oryza sativa L.) at a high level of 1% seed dry weight (10 g/kg). The recombinant human transferrin was able to be extracted with saline buffers and then purified by a one step anion exchange chromatographic process to greater than 95% purity. The rice-derived recombinant human transferrin was shown to be not only structurally similar to the native human transferrin, but also functionally the same as native transferrin in terms of reversible iron binding and promoting cell growth and productivity. These results indicate that rice-derived recombinant human transferrin should be a safe and low cost alternative to human or animal plasma-derived transferrin for use in cell culture-based biopharmaceutical production of protein therapeutics and vaccines.
BackgroundGermline mutations in the BRCA1 and BRCA2 genes account for 20–25 % of inherited breast cancers and about 10 % of all breast cancer cases. Detection of BRCA mutation carriers can lead to therapeutic interventions such as mastectomy, oophorectomy, hormonal prevention therapy, improved screening, and targeted therapies such as PARP-inhibition. We estimate that African Americans and Hispanics are 4–5 times less likely to receive BRCA screening, despite having similar mutation frequencies as non-Jewish Caucasians, who have higher breast cancer mortality. To begin addressing this health disparity, we initiated a nationwide trial of BRCA testing of Latin American women with breast cancer. Patients were recruited through community organizations, clinics, public events, and by mail and Internet. Subjects completed the consent process and questionnaire, and provided a saliva sample by mail or in person. DNA from 120 subjects was used to sequence the entirety of BRCA1 and BRCA2 coding regions and splice sites, and validate pathogenic mutations, with a total material cost of $85/subject. Subjects ranged in age from 23 to 81 years (mean age, 51 years), 6 % had bilateral disease, 57 % were ER/PR+, 23 % HER2+, and 17 % had triple-negative disease.ResultsA total of seven different predicted deleterious mutations were identified, one newly described and the rest rare. In addition, four variants of unknown effect were found.ConclusionsApplication of this strategy on a larger scale could lead to improved cancer care of minority and underserved populations.Electronic supplementary materialThe online version of this article (doi:10.1186/s13742-015-0088-z) contains supplementary material, which is available to authorized users.
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